Increased temperature risk in cities threatens the health and well-being of urban population and is fueled by climate change and intensive urbanization. Consequently, further steps must be taken for assessing temperature conditions in cities and their association with public health, in order to improve public health prevention at local or regional level. This study contributes to solving the problems by analyzing the connection between extreme temperatures and the tendencies of all-cause hospital admissions. The analyses used (a) 1-h air temperature data, and (b) daily data of all-cause hospital admissions. The datasets include the summer period (June, July, August) for the years 2016 and 2017. We tested the effects of two temperature indices, day-to-day change in maximum temperature — T max,c and daily temperature range — T r , with all-cause hospital admission subgroups, such as all-cause cases — H a , hospital admissions in the population below 65 — H a <65, and hospital admissions in the population aged 65 and over — H a ≥65. The results show the highest values of H a when T max,c is between 6 and 10 °C. Therefore, more intensive hospital admissions can be expected when T max increases from day-to-day (positive values of T max,c ), and it is more visible for H a and H a <65 (1 °C = 1% increase in hospital admissions). Also, T r values between 10 °C and 14 °C cause an increase in the number of hospital admissions, and it is more noticeable for H a ≥65.